Department of Psychology, Vanderbilt Brain Institute, Vanderbilt Vision Research Center, Vanderbilt University, Nashville, TN 37240;
Department of Biostatistics, Vanderbilt University, Nashville, TN 37240.
Proc Natl Acad Sci U S A. 2021 Dec 14;118(50). doi: 10.1073/pnas.2103702118.
Visual search is a workhorse for investigating how attention interacts with processing of sensory information. Attentional selection has been linked to altered cortical sensory responses and feature preferences (i.e., tuning). However, attentional modulation of feature selectivity during search is largely unexplored. Here we map the spatiotemporal profile of feature selectivity during singleton search. Monkeys performed a search where a pop-out feature determined the target of attention. We recorded laminar neural responses from visual area V4. We first identified "feature columns" which showed preference for individual colors. In the unattended condition, feature columns were significantly more selective in superficial relative to middle and deep layers. Attending a stimulus increased selectivity in all layers but not equally. Feature selectivity increased most in the deep layers, leading to higher selectivity in extragranular layers as compared to the middle layer. This attention-induced enhancement was rhythmically gated in phase with the beta-band local field potential. Beta power dominated both extragranular laminar compartments, but current source density analysis pointed to an origin in superficial layers, specifically. While beta-band power was present regardless of attentional state, feature selectivity was only gated by beta in the attended condition. Neither the beta oscillation nor its gating of feature selectivity varied with microsaccade production. Importantly, beta modulation of neural activity predicted response times, suggesting a direct link between attentional gating and behavioral output. Together, these findings suggest beta-range synaptic activation in V4's superficial layers rhythmically gates attentional enhancement of feature tuning in a way that affects the speed of attentional selection.
视觉搜索是研究注意力如何与感觉信息处理相互作用的主要工具。注意力选择与皮层感觉反应和特征偏好（即调谐）的改变有关。然而，在搜索过程中注意力对特征选择性的调制在很大程度上尚未得到探索。在这里，我们绘制了在单目标搜索过程中特征选择性的时空分布。猴子执行搜索任务，其中弹出特征决定了注意力的目标。我们从视觉区域 V4 记录了分层神经反应。我们首先确定了表现出对单个颜色偏好的“特征列”。在未被注意的情况下，与中层和深层相比，特征列在浅层中具有更高的选择性。注意刺激会增加所有层的选择性，但并非均匀增加。特征选择性在深层中增加最多，导致与中层相比，额外颗粒层的选择性更高。这种注意力诱导的增强与β频带局部场电位呈节律性门控。β功率主导了所有额外颗粒层的分室，但电流源密度分析指出其起源于浅层，特别是。虽然无论注意力状态如何，β频带功率都存在，但只有在注意条件下，特征选择性才由β门控。β 振荡及其对特征选择性的门控都不随微扫视的产生而变化。重要的是，β 调制神经活动可预测反应时间，这表明注意力门控与行为输出之间存在直接联系。总之，这些发现表明 V4 浅层中的β范围突触激活以一种影响注意力选择速度的方式，对特征调谐的注意力增强进行节律性门控。
